1. Field of the Invention
With reference to the classification of art as established in and by the United States Patent Office, this invention is believed to be found in the field pertaining to "Surgery" and particularly to "flexible catheter guide."
2. Description of the Prior Art
Arterial blood infusion and withdrawal devices are known and the technique of a guide wire inserted into the lumen of the artery is known and shown as prior art in FIGS. 1 A through 1 C to be hereinafter more fully discussed. A catheter placement system is shown in U.S. Pat. No. 3,416,531 to EDWARDS, as issued Dec. 17, 1968; a guide for the catheter is also shown in U.S. Pat. No. 3,547,103, as issued to COOK on Dec. 15, 1970; a flash-back indicator is shown in U.S. Pat. No. 3,942,514, as issued to OGLE on Mar. 9, 1976; a withdrawal system using a guide wire is shown in U.S. Pat. No. 4,006,743, as issued to KOWARSKI on Feb. 8, 1977; a cetheter placement assembly is shown in U.S. Pat. No. 4,046,144 to MC FARLANE, as issued Sept. 6, 1977; an extraction device is shown in U.S. Pat. No. 4,215,702, as issued to MAYER on Aug. 5, 1980; a blood collecting device with indicator is shown in U.S. Pat. No. 4,154,229, as issued to NUGENT on May 15, 1979; a needle and sheath are shown in U.S. Pat. No. 4,230,123, as issued to HAWKINS, Jr. on Oct. 28, 1980, and a guide wire placement is shown in U.S. Pat. No. 4,274,408, as issued to NIMROD on Jan. 23, 1981.
Of particular note is U.S. Pat. No. 4,417,886 to FRANKHOUSER et al, as issued Nov. 29, 1983. In this patent, in addition to Hawkins and Nimrod noted above, are referenced U.S. Pat. No. 3,995,628 to GULA; U.S. Pat. No. 4,068,659 to MOOREHEAD; U.S. Pat. No. 4,068,660 to BECK; U.S. Pat. No. 4,205,675 to VAILLANCOURT; and U.S. Pat. No. 4,306,562 to OSBORNE. In the Frankhouser disclosure, it is particularly noted the necessity of using an elongated tubular member connected to and projecting rearwardly from the proximal end of the needle. This tubular member is of a transparent, semi-rigid plastic material. Although the plastic material may have some flexibility, it should have sufficient resilience so that it maintains its tubular configuration in use. This disclosure continues: "In its preferred form, tubular member has a longitudinally extending slot running from a point adjacent the needle hub." An extending handle is adapted to be moved in this slot in the tubular member, with this handle attached to the guide wire to produce the desired movement. The Frankhouser showing does not employ an arrangement which would lend itself to or suggest a closed system with product sterility being maintained after removing the outer package or during advancement of the guide wire in the catheter.
Although the present apparatus may be used in both veins and arteries, penetration into the artery is the most difficult and requires the greater expertise. The preferred arterial catheter insertion site is the radial artery immediately proximal to the wrist. This site is preferred because the artery is relatively close to the skin and therefore relatively accessible. The position and orientation of the artery is normally located by detecting the pulse and following the pulse beat up the artery for about one inch or more in length. Some practioners draw an ink line on the skin to show this position and orientation. The catheter and needle assembly is then introduced at an angle about thirty to forty-five degrees to the surface of the skin, with the bevel of the needle facing up, or toward the outer surface.
This method of insertion is a real challenge even to the most experienced practitioner. First, he must find the artery with the point of the introducer needle and obtain flashback through the hollow of the introducer needle. Many practitioners remove the existing flash plugs in hopes of being able to obtain a quicker flashback (indication of piercing the artery). These practitioners desire a quicker flashback in the hope that this will indicate entry into the artery before penetration through the back wall of said artery with the needle point.
The artery wall is both thick (to support arterial blood pressure) and elastic and as a result the needle significantly compresses or dimples the artery wall before penetration is achieved. When the needle finally penetrates the first wall the pressure in the artery causes the wall to pop back along the needle, leaving minimal resistance to further forward travel of the needle. The most common occurrence is for the point of the needle to bury itself in the back wall of the artery when the first wall of the artery "pops" back over the heel of the bevel and along the shank of the needle. To compensate for this, some practitioners actually twist the introducer needle about its axis after they have observed flash in the introducer hub. This maneuver is intended to orient the main bevel angle parallel to the back wall of the artery and lift the embedded point out of the back wall. Other practitioners tend to draw the introducer needle back after they see flashback on the assumption that the point is embedded into the back wall of the artery.
Once the practitioner has observed flashback in the introducer and has been able to slide the catheter forward a short distance on the introducer, he assumes that he is in the artery with the tip end of the catheter. At this point, however, it is not just a simple matter of sliding the entire assembly or the catheter alone up the artery as the axis of the introducer needle is disposed at a substantial angle to the axis of the artery. This needle, when and as positioned, cannot be advanced up an artery or vessel. Rather, the practitioner utilizes a delicate feel to slide the catheter off of the introducer needle and into and up the artery. This procedure requires the advancing catheter to bend at its point of entry into the artery. Many times the catheter becomes embedded in the wall of the artery and the practitioner must detect this problem by the feel of the catheter as the catheter is slid forward. If the practitioner does not follow this procedure a substantial risk of gouging the lining of the artery and inducing a severe thrombosis occurs.
In order to get the catheter into the artery the catheter is bent so as to follow the artery. At this point the practitioner usually retracts and readvances the introducer several times during each insertion and puncture of the artery. Each placement may entail half a dozen unsuccessful attempts. Each failed attempt further aggravates the problem, because the artery goes into "spasm." After a few unsuccessful attempts, the user gives up using the catheter unit in the started attempt and with a fresh new unit begins again. In a sampling of hospitals it was found that over two needle-catheter units were used to achieve each successful catheter placement as a further indication of how difficult it is to successfully place catheters in the artery.